During the electrolysis of water, two product gases hydrogen and oxygen are formed simultaneously. These product gases must be separated, and must not be mixed with one another. Membranes of the electrolyzer may develop leaks during operation, and then hermetic separation of the two product gases can no longer be ensured. In this case, mixing of the product gases may occur, so that in the extreme case an unsafe operating state may arise. This eventuality must be prevented by suitable measures.
Leaks of membranes of an electrolyzer may, for example, be detected by checking whether a product gas penetrates through a membrane. This procedure requires separate monitoring of the product gases and is relatively expensive. A challenge in the case of an electrolyzer for water electrolysis is, in particular, that water is present in the system, so that together with the two product gases up to three components may be present simultaneously. In a dynamic process, which generally entails temperature and pressure changes, the water content sometimes varies greatly. This makes calibration more difficult, particularly in the case of simple analysis methods. Furthermore, undesired condensation may occur. In a typical technical implementation of the monitoring of the product gases to detect membrane leaks, a relatively small gas flow, diverted from a product gas, is analyzed. With the aid of an actively cooled condenser, for example, the diverted gas can be dried. Time-varying operating pressures can be regulated by a pressure reducer. For example, gas chromatographs, thermal conductivity detectors, or catalytic sensors may be envisioned as detectors. In the presence of hydrogen and oxygen, the latter cause a chemical reaction and thereupon register a temperature increase. Such a procedure has the disadvantage that additional components are required, and that relatively elaborate calibrations need to be carried out.